Conventional methods for exposure of photographic materials to light include an image forming method using a scanner system. Therein, the original is scanned, and a silver halide photographic material is exposed to light based on the resulting image signals to form a negative image or a positive image corresponding to that of the original. Many recording devices which practically use such a scanner system type image forming method are conventionally known. Light sources which are conventionally used for the recording of the scanner system type recording devices include glow lamps, xenon lamps, mercury vapor lamps, tungsten lamps and light-emitting diodes. However, these light sources are disadvantageous in that their output is low and their working life is short. Scanners and laser printers are known where exposure to light is conducted under high illumination conditions using coherent laser beams such as He-Ne laser beams, argon laser beams and He-Cd laser beams as light sources for the scanner system to remedy the above-described disadvantages. However, although providing a high output, these scanners and laser printers are disadvantageous in that the devices are large-sized and expensive and a modulator is required. Additionally, because the illumination source for exposure emits visible light, there is a limit to safelight use for the photographic materials, and handleability is also poor.
On the other hand, semiconductor lasers are small-sized and inexpensive, modulation is easily conducted, and semiconductor lasers have a working life which is longer than that of the foregoing lasers. In addition, a safelight is advantageously used with semiconductor lasers which emit light in the infrared region. Thus, handleability and workability are improved.
Dyes which absorb light in the infrared region are generally used to prevent halation, to thereby reduce blurring of the image due to exposure to infrared light. Practically, the dyes can remain in the photographic material after processing, so long as the dyes do not absorb visible light. However, the dyes usually absorb some visible light, and a residual color is formed when the dyes remain in the photographic material after processing. The formation of the residual color is practically not preferred. Accordingly, water-soluble dyes are used as the antihalation dyes.
When water-soluble dyes are used in layers on the same side of the support as that coated with silver halide emulsions, the dyes diffuse into the silver halide emulsion layers. Consequently, sensitivity is greatly lowered.
To solve this problem, a method has recently been proposed wherein dyes which are decolorizable in the development processing stage are dispersed in the form of fine solid particles to fix the dyes to a specific layer [See, (PCT)WO 88/04794, European Patent (Laid-Open) Nos. 0,274,723A1, 276,566 and 299,435, JP-A-52-92716 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-55-155350, JP-A-55-155351, JP-A-61-205934, JP-A-48-68623, U.S. Pat. Nos. 2,527,583, 3,486,897, 3,746,539, 3,933,798, 4,130,429 and 4,040,841, Japanese Patent Application No. 1-50874, JP-A-2-282244, JP-A-3-167546 and JP-A-4-180057].
However, dyes which absorb light in the visible wavelength region are mainly disclosed in the above patent specifications. Even where dyes which absorb light in the infrared region are disclosed, it has been found that the dyes specifically exemplified therein are not sufficiently fixed to a specific layer.